A marked improvement in the production and growth rates of confined poultry or other livestock is noted if the confinement houses are regularly and evenly ventilated. As a result, the practice of providing some means of regulating the flow of air into and out of a confinement house has been widely adopted for some time. In accordance with the prior art known to Applicant, exhaust fans or the like are actuated in response to a temperature sensing apparatus which turn the fans on when a preselected temperature is reached. The exhausted air is replaced through various inlet arrangements generally positioned along the upper margin of the confinement house so that the fresh air flowing in is drawn downwardly over the livestock confined therein for exhaust beneath or along the lower margin of the building.
A principal disadvantage with present arrangements is the lack of a simple and yet meaningful control over the air inlet mechanism. At each level or rate of exhaust, there is a corresponding optimum inlet opening to provide the proper balance for replacement air. If the opening is larger than required, insufficient mixing is achieved. That is, the movement of the incoming air will be insufficient to reach the innermost and lowermost extremities of the building therefore causing an overcooling with respect to the livestock near the inlet ducts and insufficient cooling or ventilation with respect to the livestock removed from the inlet ducts. On the other hand, if the inlet opening is too small, the pressure differential across the inlet opening caused by the exhaust fans result in the inlet air flowing at a higher velocity than is desired. Thus, the distribution of fresh air into the confinement house is many times uneven and therefore results in the development of stagnant areas which are never properly ventilated.
One approach taught by the prior art is to vary the rate of flow by varying the inlet opening so that a given differential in air pressure between the interior of the building and atmosphere is automatically maintained throughout variations in air discharge rate. While this is desirous, it does not assure efficient and even ventilation since the inlet configuration will develop different stratifications and zones of air movement or even dead zones depending on the rate and volume of air flow. For example, air being sucked into a building through a window diffuses in all directions at approximately an 11.degree. angle losing most of its speed whereupon it is drawn directly to the fan leaving large areas within the building unventilated. By positioning the inlet opening at the ceiling, the rate of flow through the opening will maintain its speed longer because it is only diffusing in three directions (down, to the right and left) instead of four. It will still however develop undesirable zones of unventilated air space within the building.
Uneven distribution of fresh air results in an inconsistent production or growth rate by the livestock. Of equal importance, the inefficiencies resulting from the inaccuracies provided by present proposals has in many instances required utilization of more and heavier duty exhaust fans than would be required if the replacement air were properly and evenly distributed. This results in higher overall costs in the systems which costs are not negligible. Thus, there is a need in this art for a ventilation system which provides an easier and simple means which more efficiently distributes and mixes the fresh air flowing through the air inlet to prevent uneven distribution of the fresh air.